I. Field of the Invention
The present invention relates to stove and heater devices and, more particularly, to stove and heater devices for camp use with foraged fuel.
II. Description of the Prior Art
Frequently, outdoorsmen such as fishermen and hunters spend a considerable amount of time in a particular location during cold weather. Containers for building fires for cooking food and heating the body while outdoors are well known.
Problems with prior art devices include that they are subject to blow out or sparking in windy conditions. Many have vents that permit direct air access to combustible material, allowing wind to blow directly onto flames causing sparks and burning material to be ejected creating a fire hazard. Often devices are designed such that hot or burning material may fall out of the bottom.
Other problems with prior art include the fact that the exterior of the device while in use will become hot enough to quickly ignite material on contact creating a fire hazard.
Previous designs have also required or contained cross-welded or joined members. In the heating of a cylinder, there is often thermal expansion. Prior art devices have suffered from uneven expansion of components that leads to metal fatigue and component failure, particularly at welds.
The present invention provides a stove or heater that burns foraged fuel efficiently and safely. The device is sturdy and easily constructed. The device also provides improved safety over prior art, reducing the risk of uncontrolled burning.
The construction of the device is such that all primary components may be joined on a floor, largely by the use of non-welded metal tabs. Items subjected to thermal stress expand and contract causing wear and fatigue leading to component failure. There is a useful need for a stove that is assembled in manner that permits free expansion of components under heat.
The device provides improved combustion of fuel. Warmed air burns more readily. The present device channels warmed air to both a primary burn chamber where fuel is consumed, and also provides an alternate air pathway for air to be warmed and fed into the hot gasses expelled from the burning fuel for secondary combustion.
Safety features of the device include a layout of the components that provide an inexpensive system of guardrails for ease of handling and moving the device and to prevent inadvertent contact with hot components. The multiple walled structure of the device also permits useful radiant heat from the outer wall, without developing a dangerously hot surface.
Additional safety features and improved characteristics are in the series of offset vents that supply air to the primary and secondary burn areas. Wind is not permitted to blow directly into the burn chamber and thus excessive sparking is avoided. The bottom half of the unit is also completely enclosed so that there is no spillage of burning or hot fuel or ash.
The present invention provides a compact and easily transportable camp stove and heater device. A multi-walled container having an elongated cylindrical body with an opening at a top end and a closed bottom portion is provided for containing fuel and a fire. The container is comprised of a series of nested wall, including an outer wall, a middle wall and an inner wall. The walls have a series of vents to provide air to the burn chamber located within the inner wall.
The nested walls are concentric. Each wall is affixed to a floor. The floor is to both contain and define the lower boundary of the burn chamber and provide an air chamber between the floor and a base plate that extends beyond the floor and the outer diameter of the outer wall to improve stability.
The inner wall is capped with an inner cap. The inner cap is generally ring shaped with a central opening. The inner cap defines the upper boundary of the burn chamber. The central opening of the inner cap provides access to the burn chamber for the insertion of fuel and removal of waste and ash.
An outer cap caps the device displaced above the inner cap. The outer cap is also generally ring shaped with a central opening. In the preferred embodiment the outer cap is placed above the inner cap so as to permit airflow, but placed below the upper edge of the outer wall so that the outer wall extends above the outer cap forming a raised lip.
The vents of the device are located so as to provide a more efficient stove with improved safety characteristics. The vents on the outer wall are located medially, with a distance of the outer wall both above and below the outer wall vents.
The middle wall vents may be located at any point. In the preferred embodiment the middle wall vents are in the form of horizontal slots located in the lower portion of the middle wall.
The inner wall vents are located proximate the base plate. In the preferred embodiment they are vertical slots placed equidistant around the circumference of the inner wall extending upward.
The vents of each of each of the three walls comprise an approximately equal area to permit clear airflow. This preferred area is the approximate area of the inner cap central opening. The cross sectional area available for airflow between the inner cap and the outer cap is also of this same approximate area.
Assembly is principally through the use of non-welded tabs. The majority of the components are held in place by the use of receiver slots and metal tabs permitting expansion of contraction of the elements when under thermal stress.